I spend about 90 minutes a day on public transport - and I often while away the time 'preparing food'.
I start with a rough idea, then mentally go through the steps to make it - often back tracking and modifying details or even starting again if it all seems to be going awry or too boring. I end up 'eating' the dish mentally, and if it tastes good (yes I'm that crazy) I write a mental shopping list for the ingredients I don't already have in stock.
Sometimes I 'make' the same dish over and over until I am happy with it, because only then will I take the plunge and try it out for real. Often I don't ever make the food (a lot of the 'recipes' are too unhealthy or expensive) - and on a few occasions I have come up with something that was just as yummy as I imagined it. Many times I just 'make and eat' something just for the pleasure of it, especially when I'm on my way home to a plate of boring leftovers. Oddly it makes the real food better, maybe because by the time I get home I am ravenous.
Does anyone else out there do this, or is it just me?